One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10)(11,18)(12,22)(13,19)(14,17)(15,16)(20,21)(23,24)(25,26)(27,35)(28,39)(29,33)(30,34)(31,38)(32,37)(36,40) involution — undirected(1,2)(3,7)(4,8)(5,6)(9,11)(10,13)(12,20)(14,21)(15,19)(16,18)(17,23)(22,24)(25,27)(26,31)(28,36)(29,37)(30,38)(32,40)(33,39)(34,35) involution — undirected(1,3,5,4)(2,7,6,8)(10,16)(11,19)(12,17)(21,24)(25,26,30,34)(27,31,38,35)(28,32,37,39)(29,33,36,40)(1,3,5,4)(2,7,6,8)(9,12,15,17)(10,14,16,22)(11,20,19,23)(13,21,18,24)(25,26)(27,31)(28,32)(29,33)(30,34)(35,38)(36,40)(37,39)(9,13)(10,11)(12,21)(14,20)(15,18)(16,19)(17,24)(22,23)(25,28,30,37)(26,32,34,39)(27,36,38,29)(31,40,35,33)(1,4,5,3)(2,8,6,7)(9,14)(10,17)(11,21)(12,16)(13,23)(15,22)(18,20)(19,24)(25,29,30,36)(26,33,34,40)(27,37,38,28)(31,39,35,32)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.